LAUSR

OBJECTIVE Phonological working memory impairments associated with attention-deficit/hyperactivity disorder (ADHD) have garnered interest due to reliable evidence of moderate- to large-magnitude between-group (ADHD vs. control) effects, as well their association with a wide range of secondary impairments. However, previous studies are methodologically limited in their ability to identify potential underlying mechanistic processes. This study aimed to examine converging and diverging patterns of omission, intrusion, and transposition errors to parse-specific mechanistic processes that contribute to ADHD-related phonological working memory deficits. METHOD Fifty-four children with ADHD (45 males, nine females) and 65 typically developing (TD; 50 males, 15 females) children aged 8-12 (M = 9.62, SD = 1.52) years completed a computer-based phonological working memory task that aurally presented a random series of jumbled numbers and one letter. Children were instructed to verbally respond by stating the numbers from least to greatest, followed by the letter. Children's incorrect responses were coded as errors of omission, intrusion errors, or transposition errors. RESULTS Results indicated a significant moderate-magnitude between-group difference in total omission and transposition errors, and a significant small-magnitude between-group difference in total intrusion errors. An examination of specific error types supported evidence of ADHD-related deficits in reordering and updating central executive processes. CONCLUSION Collectively, these findings contribute to a more precise understanding of underlying mechanistic processes in ADHD-related working memory deficits and hold potential to inform the development of novel working memory metrics and working memory-based interventions for ADHD. (PsycInfo Database Record (c) 2023 APA, all rights reserved).